Creams are conventionally composed of an emulsion. Emulsions comprise an aqueous phase and an oily phase dispersed in one another. Oil-in-water (O/W) emulsions, the external phase of which is the aqueous phase, are more particularly desired because they contribute more freshness on application than water-in-oil (W/O) emulsions comprising an oily external phase. Their feel and their application seem to be less greasy than those of a W/O emulsion. In addition, they make possible a high level of moisturizing, which is particularly useful in caring for dry skin or lips.
In order to confer a novel texture on emulsions, attempts have been made to introduce a gas, generally air, therein in order to confer on them a light texture and to give them the appearance of foam. This is what is known as aeration. The aerated emulsions obtained are appreciated for their lightness on skin feel and ease of application, more specifically on ease of spreadability without dragginess. Nevertheless, they exhibit the disadvantage of being relatively unstable because of their low relative density and thus of separating out after a certain storage time. The document CH-A-674,804 discloses stabilization of an aerated cosmetic cream comprising an inert gas or air by the addition of an aqueous solution of a protein of animal origin. However, the use of such proteins is avoided in cosmetics.
Furthermore, the document JP-A-56/079613 discloses stable aerated surfactant-free compositions comprising from 5 to 20% of waxes, preferably waxes with a high melting point. The emulsions obtained are then stable but exhibit cosmetic properties which are unacceptable to the user. This is because these compositions comprise very little water and therefore lack freshness when applied to the skin. In addition, they comprise a significant amount of humectants, such as glycerol, which leads to a feeling of stickiness to the touch. In addition, the use of a wax with a high melting point in an amount of 5% results in heavy textures which are very difficult to apply to the skin.
The need thus remains for an emulsion which has the appearance of foam, while comprising a large amount of water, and which is fresh and not sticky when applied to the skin.